Internal sewer-form.



L. E. KOEHLER-GL'T. P. THOMSON. INTERNAL" SEWER roam.

APPLICATION FILED MAR. l. 1915.

1,185,915. Patented June 6,1916.

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LEO E. KOEI-ILER AND THOMAS P. THOMSON, OF KANSAS CITY, MISSOURI.

INTERNAL SEWER-FORM.

Specification of Letters Patent. Patemt gd June 6, 1916 Application filed March 1, 1915. Serial No. 11,185.

To all whom it may/concern Be it known that we, LEO E. KonHLEn and THOMAS P. TI-ioMsoN, citizens of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Internal Sewer-Forms, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same. K

The invention relates to formsfor the internal formation of sewers and the like and seeks to provide a simple and efficient form of sufficient rigidity to maintain a true shape under the excessive strains due to pouring concrete and the like upon it, slightly collapsible for removable purposes, and light enough in weight so that sizes ranging to seven feet in diameter and above may be easily handled without the aid of lifting devices other than the hands of the workman.

Collapsible forms as constructed heretofore have been so complicated as to prohibit their use by the class of workmen usually employed in sewer construction, and the multiplication of parts has made them weak with comparative weight, while the adjust able features have not produced a desirable uniformity in the size and shape of the sewer constructed upon them.

The present invention has provided an improved internal form for the construction of concrete sewers and the like, comprising duplicate units that may be connected in any desired length, rigid collapsible supporting members and a collapsible casing with means to force the collapse thereof for removal purposes. These forms have proved very desirable to the contractor owing to the extreme low cost of production, and the ease and rapidity with which they are set up before pouring the concrete and removed after the concrete has set, the final result being a great financial saving in the cost of constructing the sewer.

With these and other objects in view the invention consists in the features of construction, combinations and arrangements of parts hereinafter set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

In the drawings :Figure 1 is a view of a series of units of the improved form partly in elevation and partly in section, the section being taken on line a-a of Fig. 2. Fig.2 is a sectional view taken on line bb of Fig. 1. Fig. 3 is an enlarged fragmentary internal view looking outward,

showing the rigid connection of one of the t supporting rings.

The supporting rings 1 are preferably of standard channel shaped bars bent to a practically true circle with the ends 2 and 3 slightly separated as shown and heldrigidly in this position by the clamp plate t hinged on the bolt 5, the latter passing through the ring, the elongated hole 6 in the clamp plate fitting over the stud bolt 7 and held in rigid position by the nut 8, so that the ring cannot collapse when connected with the clamp plate.

The collapsible shells 9 are preferably of sheet metal of suiiicient thickness to sup port the concrete that is to be poured thereon, the end 10 of the shells overlapping the end 11, the hooks 12 being secured to the internal surface of the shells by rivets 13, and the turnbuckle 14c connecting the hooks for the purpose of drawingthe shell tight upon the ring 1 so that it will be round and true. I

The lugs l5 are riveted to the shell 9 by rivets 16 and serve as a stop and rest for the ring 1 so that an evenlap of the shells may be secured on the ring, the lugs also serving to rigidly connect a series of shells together by the draw rods 17. The form is preferably supported by the concrete block 18 which is embedded in the concrete as it is poured and becomes a part of the monolithic mass of sewer construction.

It will be understood that the outer forms sometimes consisting of the ground are used to support the outer surface of the concrete as it is poured, but'this forms no part of the present invention.

In practice it has been desirable to set up a sufficient number of the shells 9 supported by the rings 1 to comprise a continuous form long enough to keep the workmen employed pouring concrete for-about two days after which the shells from the concrete first poured may be removed and con nected to the opposite end of the form, making the work of constructing long sewers continuous.

To remove the form from within the concrete the rods 17 and nut 8 are removed and clamp plate 4 turned as indicated in dotted lines of Fig. 2, when the ring 1 will collapse until the ends 2 and 3 meet which will allow the ring to be easily removed from the shell owing to the fact that the shell adheres to the concrete and will not collapse until forced to do so. After the rings 1 have been removed from any one of the shells 9 the turnbuckle 14 may be tightened and the shell forced to part from the concrete and collapsed sufficiently to allow of easy removal.

The rings 1 are made nonadjustable for the reason that adjustable rings cannot be maintained in a true circle in both contract ed and expanded positions, also in large diameters it is advantageous to maintain a certain size so that the contractor may figure the amount of concrete required for the construction as a further reason it is eX ceedingly advantageous to eliminate adjustable parts as a matter of reducing the first cost, the cost of maintenance and the cost of setting up and taking down, the latter operation being one of almost continuous performance during the construction of a sewer.

The ends 10 and 11 of the shell 9 may overlap sufficiently to serve plural sizes of the ring 1, for instance a seven foot diameter and an eight foot diameter ring may be employed with the same shell, it not being desirable to adopt one shell to plural. rings of too great a difference in dimensions, and all the rings are usually of one diameter in one form.

It is obvious that changes may be made in the details as set forth without departure from the essentials of the invention.

What we claim as new and desire to secure by Letters Patent, is

1. In internal sewer forms the combination of, a resilient ring integral from end to end, a clamp plate hinged to and near one end of said ring and arranged to swing ap proximately in the plane of the diameter of said ring, a hole in said plate, a bolt projecting from near the opposite end of said ring and positioned toenter said hole when said plate is positioned to connect the two ends of said ring, a nut to clamp said plate rigidly to said ring and hold said ring in slightly expanded position, said ring being slightly collapsible when said nut is removed and said clamp disengaged, a sheet metal shell supported by said ring, and said ring being withdrawable from said shell when collapsed 2. In internal sewer forms the combination of a series of shells, each shell abutting the adjacent shell, a ring within and supporting the ends of each of the abutting shells, lugs within said shells, said lugs spacing said rings, and drawrods connecting said lugs and holding said shells and said rings in operative position.

3. In internal sewer forms the combination of plural one piece rigidly connected rings, plural shells encircling said rings and separable thereon, a turnbuckle within each of said shells and adapted to draw the respective shell tight around said rings and to pull said shell from the concrete after the rings are removed, and means for holding said rings in place and drawing the ends of said shells together.

In testimony whereof we affix our signatures in the presence of two witnesses.

LEO E. KOEHLER. THOMAS P. THOMSON. Witnesses G. C. DYER, L. F. WYRIOK.

Copies oi this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

